Preheat the oven to 475 degrees Fahrenheit. Spray the nonstick baking sheet with the cooking spray.

Cut the potatoes lengthwise into quarters then cut into 1/4-inch slices. Set the potato on the baking sheet. Pour the oil over the potatoes. Season with the rosemary and garlic powder. Gently spray with the cooking spray.

Bake for 8 minutes then flip them over and cook for another 7 minutes. Once they are done cooking, place them in on a paper towel for 1 minute before serving.